Apparatus for longitudinal reciprocation of a mold for continuous casting



Dec. 20, 1966 A. K. TAYLOR ETAL 3,292,215 APPARATUS FOR LONGITUDINAL RECIPROCATION OF A MOLD FOR CONTINUOUS CASTING Filed May 19, 1964 6 Sheets-$heet 1 1966 A. K. TAYLOR ETAL 3, 92,

APPARATUS FOR LONGITUDINAL RECIPROCATION OF A MOLD FOR CONTINUOUS CASTING Flled May 19, 1964 6 Sheets-Sheet 2 Dec. 20, 1966 A. K. TAYLOR ETAL 3,292,215

APPARATUS FOR LONGIIUDINAL RECIPROCATION OF A MOLD FOR CONTINUOUS CASTING Filed May 19, 1964 6 Sheets-Sheet 3 1966 A. K. TAYLOR ETAL 3,292,215

APPARATUS FOR LONGITUDINAL RECIPROCATION OF A MOLD FOR CONTINUOUS CASTING Filed May 19, 1964 6 Sheets-Sheet 4 Dec. 20, 1966 A. K. TAYLOR ETAL 3,292,235

APPARATUS FOR LONGITUDINAL RECIPRQCATION OF A MOLD FOR CONTINUOUS CASTING Filed May 19, 1964 6 Sheets-Sheet 5 Dec. 20, 1966 TAYLOR ETAL APPARATUS FOR LONGITUDINAL RECIPROCATION 6 Sheets-Sheet 6 Filed May 19, 1964 Q Q G k P & R R 2 m a M? Q h l 1 1 \I M N w Q 1% R k United States Patent 3,292,215 APPARATUS FOR LON GITUDINAL RECIPROCA- TION OF A MOLD FOR CONTINUOUS CASTING Alan K. Taylor, Workington, Cumberland, England, and

Alfred Turnovszky, Zurich, Switzerland, assignors to Concast AG., Zurich, Switzerland Filed May 19, 1964, Ser. No. 368,482 4 Claims. (Cl. 22-57.2)

This invention relates to continuous casting of metals and, more particularly, relates to apparatus for reciprocating the continuous casting mold in a reciprocation cycle in which the speeds of the forward and the return stroke differ from each other.

Mold reciprocation ensures various advantages, resulting in an increased output and an improved quality in continuous casting.

With continuous casting machines, the liquid steel is poured into an open-ended cooled mold which cools the metal periphery to form a solidified skin defining a strand, exiting from the mold in continuous manner. The strand is then further cooled and is guided afterwards, straight or bent, to a discharge place where the fully solidified strand is cut or further worked. As known to the art, the casting mold is preferably reciprocated to ensure more eflicient operation of the plant.

Two principal types of mold reciprocation oscillation cycles are known: the symmetrical and the unsymmetrical reciprocation cycles.

With the symmetrical cycling, which is generally produced by an eccentric, the mold is reciprocated so that the forward and the return stroke are of equal speed, i.e. the ratio of reciprocation is 1:1.

With the unsymmetrical cycling, which is generally produced by a cam, the forward and the return stroke of the mold is of unequal speed, resulting in an unequal ratio of reciprocation stroke speeds, which in most cases is 1:3. The unsymmetrical reciprocation cycle involves high accelerations and decelerations.

As compared with unsymmetrical cycling, symmetrical cycling has the disadvantage that the relative motion between strand and mold is both equal and relatively large during forward and return stroke, resulting in inferior heat transferand, thus, lower casting speed. The favorable conditions of the inertial forces can be considered as an advantage of symmetrical cycling. Unsymmetrical cycling gives rise to large inertial forces which, for mechanical reasons, limit the casting speed.

The reciprocation ratio and the stroke length of the mold are, to a large extent, dependent on the quality and the dimension of the metal to be cast. Therefore, different solutions have already been suggested to alter the stroke length or the reciprocation ratio. These suggestions, however, do not permit the two variables to be altered individually or simultaneously without changing parts. Exchanging the cam requires a corresponding stock of expensive cams, in addition to the disadvantage of discontinuous adjustment. As a rule, not only must a cam be changed but also the link motion must be readjusted.

It is, therefore, the object of the present invention to provide an improved apparatus to reciprocate the continuous casting mold in which adjustment of the speed of forward and return strokes as well as the stroke length is quickly and easily accomplished.

In accordance with this object, there is provided, in av preferred embodiment of this invention, a continous casting mold slidably mounted on guides extending along the axis of the mold. A push rod is provided to drive the mold in a reciprocation cycle. To actuate the push rod, there is provided a beam pivoted about a fixed pivot. The push rod is slidably coupled to the beam and the Patented Dec. 20, 1966 ice beam is oscillated by a swinging block linkage having a driving means, such as a crank, slidably coupled to the beam in such manner that the lever arm between the pivot and crank coupling changes during the reciprocation cycle between a maximum and minimum length.

This apparatus permits the conversion of a rotating driving movement to a sinusoidal deflection of the mold, with unequal speeds of the forward and the return stroke, whereby optimum conditions with the mass forces are achieved. These optimum conditions permit an increase of the casting speed without vibration of the mold which leads to breakouts.

According to a preferred feature of the invention, the throw of the drive means, the beam arm to the push rod, and the beam arm to the drive means are adjustable. This adjustability can be achieved in such a way that adjustments can be effected during the operation of the machine, which permits rapid adjustment of the ratio between the return and forward speeds to the casting conditions.

In accordance with a further feature of the invention, the distance between the connection of the mold and the fixed axle can be adjustable, thus, permitting an adjustment of the stroke. The latter is necessary to balance the changes of stroke caused by the adjustment of the reciprocation ratio. The adjustment of the throw of the crank can also be used to adjust the stroke. This adjustment of the stroke can be arranged in such a way that it can be done during the operation of the machine.

These adjustment possibilities eliminate the need for spare cams, which is a great advantage, as such cams are expensive and due to the line contact between the cam and cam follower are worn out much more rapidly than the cranks or eccentrics of this invention with their surface contact.

A special compact construction is charaterized by a crank or an eccentric and two lever-like parts in two different planes onnected with each other by a supported shaft, the first of which is connected to the eccentric or crank by means of a block, movable in the lever-like parts at least over a range of twice the radius of the crank or twice the eccentricity of the eccentric, and the second lever of which is connected with a push rod to drive the mold.

The transmission of the movement from the lever to the mold is preferably achieved by a push rod, movable only in longitudinal direction, the bearing block of which is adjustable in transverse direction to the push rod, if necessary. With this arrangement, an adjustment of the stroke is possible.

Other object and advantages of this invention will be described in greater detail in the following portions of the specification, which may best be understood by reference to the accompanying drawings, of which:

FIGURE 1 is a side elevation of a continuous casting plant using the present invention;

FIGURE 2 is an end view of a portion of the apparatus shown in FIGURE 1;

FIGURE 3 is a section on the line III-III in FIG- URE 2;

FIGURE 4 is a section on the line IVIV in FIG- URE 3;

FIGURE 5 is a schematic useful in explaining the principle of operation of the present invention;

FIGURE 6 is a curve showing the velocity of the mold plotted against the angular position of the crank; and

FIGURE 7 is a side elevation of another embodiment of the invention.

In FIGURE 1, there is shown a mold 1, into which the liquid metal is poured. This mold is mounted on a table 2, linked to structure 3 by way of guides. The

ported in disc 12.

table 2 is connected with one end of a lever 4 being pivoted at 5 in the structure 3 and serving to reciprocate the mold.

The other end of the lever 4 is pivotally connected at 6 to one end of a rod 7, which is made in two parts interconnected by a threaded sleeve 8, so that the length of the rod 7 can be varied by turning the sleeve 8. This push rod is pivotally connected at 9 to the head piece 10 of a push rod 11.

FIGURES 2-4 show the apparatus for reciprocation of push rod 11. This mechanism comprises a crank 12 formed by a disc 12 mounted on a shaft 13 which is driven by an electric motor not shown. The disc 12 carries a crank pin 14 which is surrounded by a needle bearing 15, the outer race 16 of which is fixed in a hollow rectangular frame 17 which forms a sliding block. This block 17 slides between parallel guides 18 which form facings on two arms 19 of an open rectangular frame 20, representing the first lever-like part. This frame 20 is keyed to a shaft 21 mounted to turn on hearing 22. R0- tation of the shaft 13 causes the frame to oscillate While the block 17 slides in guide 18. i

The shaft 21 terminates in a disc 23 which can turn in needle bearing 24 in a fixed part 25 of the casing. The needle bearing 24 is held by an annular face plate 26 in the fixedpart 25. The disc 23, is slotted (slot 27). A sliding block 28 having bearing facings 29 slides in the slot 27 and comprises a pin 30 which connects with a boss 31 on rod 11.

The principle of operation of this mechanism-is shown in FIGURE 5. As the crank constituted by the disc 12 rotates, the first lever-like part 20, the rotation center of which forms the shaft 21 and is outside the pitch circle of the crank 12, is rocked between the angular positions shown at 20 and 20". These correspond to positions 12' and 12". The first lever-like part 20 forms one arm of a bell-crank lever, the other arm of which is formed by the slotted disc 23 (representing the second lever-like part). The second lever-like part 23 follows the movement of the first lever-like part 20, imparted by the crank 12. The sliding block 28 slides in the slot 27 as the second lever-like part 23 rocks and the mold is reciprocated via push rod 11. The upward movement of the mold takes place during the clockwise movement of the crank 12 from 12 to 12" and the downward movement during the movement from 12 to 12. 7

FIGURE 6 shows the velocity curve of the mold plotted against the rotation of crank 12, and, therefore, of driving shaft 13. The ordinate shows the mold speed and the abscissa the angular position, whereby position 12 is considered as zero. This speed curve results from thefact that the working length of the lever, and therefore, the speed ratio between crank 12 and fixed axle 21 varies from a minimum to a maximum during one rotation of the crank.

For FIGURES 5 and 6, it is assumed that the ratio of speeds of the mold when moving upwards to that when moving downwards is 3:1 so that the angle between the crank positions 12' and 12" is 90 degrees and that between 12" and 12 is 270 degrees. The mechanism shown allows this, ratio to be varied extremely easily without changing any parts. Such adjustment is made possible by the mounting of an adjustable crank pin 14 on crank 12. The pin 14 is fixed on a block 32 which fits in a dovetail groove 33 in disc 12 and receives a threaded rod 34. This threaded rod extends through the disc 12. At one end outside the disc, a lock nut 35 is provided. A collar 36 prevents longitudinal displacement of the threaded rod 34. At the other end, the rod 34 carries a collar 37 sup- If this rod 34 is turned, the block 32 moves along the groove 33. The radius of the crank and, thus, the angle between the crank positions 12' and 12" and, therefore, the ratio of the upward and downward stroke is altered. Access to the rod 34 is made possible by a hinged cover plate 38 in the casing. As due to the adjustment of the ratio, the stroke is altered as well, the stroke must be readjusted as follows.

According to one embodiment of the invention, the,

mold stroke is made adjustable during the operation of the machine without removing any parts. pose, the push rod 11 is longitudinally movable in guide 47. This guide 47 is formed by a block 48 fixed to a backing plate 39. A threaded bush 40 is fixed in this.

block 48 and receives a threaded rod 41 whichis piv-t otable in bearings 42 and 43 and carries a hand-wheel.

44. The plate 39 engageswith guides 45 weledto a part 46 of the frame. 48 and, thus, the guide 47 is moved, thereby altering the. distance between the boss 31 and the shaft 21. This adjustment alters the working length of the lever or the second lever-like part 23 and, thus, the stroke of the mold.

This adjustment can be performed independently from the alteration of the stroke or may serve to readjust the stroke after changing the reciprocation ratio.

FIGURE 7 shows a curved mold 51 for the produc This mold is carried by a beam L 52 which is pivoted at the center of curvature of the mold (not shown) and moved by a push rod 53. This rod is pivotally connected to a sleeve 54 which can slide in. the beam 52, e.g. at a bar 55 that spans two cross memtion of a curved billet.

bers 56.-

It will be understood that, if instead of the straight mold 1 shown in FIGURE 1, a curved mold is used, it

must be carried by a beam which may be reciprocated by a rod. Therefore, to reciprocate the rod 53 as shown in FIGURE 7, the mechanism described in FIGURES ,2-4 1 may also be used.

whereby the block 60 slides in the guides fixed in the lever 57. e

The motion of the lever 57 is transmitted to the rod; 53, thelower end of which is pivotally connected to a block 66. Thereby, the block 66 slides on a rod 64 t which is connected to transverse members'65 fixed to the.

lever 57. The push rod 53 passes through a guide 67 and This 'guide 67 can be moved transversely to the rod 53 by a threaded rod is only movable in longitudinal direction.

68, which is linked to guide 67 by a threaded boss 69..

The threaded rod 68 is connected to supports 70. By

turning the wheel 71, the stroke of the mold, as described for FIGURES 2-5, can be altered during the casting in the,

same way as that of the mold 1.

The support 59 has a threaded bore which receives a threaded rod 72 that is carried in supports 73 and can be turned by a hand-wheel 74. By turning this wheel, the distance between driving shaft 62 and the shaft 58 and, thus, the ratio of the forward and return speeds of the mold, can be altered. If the support 59 is moved to its extreme right-hand position, the extreme positions of 0scillation of the lever 57 are those noted as 57 and 57". If the speed ratio is altered by moving the support 59, the stroke will also be altered. If it ought to remain the same, the guide67 must be adjusted in position at the same time.

The mechanisms shown in FIGURE 7 is particularly suitable for machine used for casting large cross-sections.

This invention may be variously modified and embodied within the scope of the subjoined claims.

What is claimed is:

l. A continuous casting apparatus comprising a mold, guide means defining the oscillation path of said mold, rotary drive means, said rotary drive means being provided with a pin eccentric to the axis of rotation thereof, a pivotably mounted first lever, a first sliding block slidably mounted within said first lever and engaged by said eccentric pin on said rotary drive, the path of movement For this put-J By turning the wheel 44, the block 1 of said first sliding block within said lever being confined to and displaced to one side of the pivot point of said first lever to convert the rotary motion of said rotary drive transmitted through the eccentric pin engagement with said first sliding block to oscillatory motion of said pivoted first lever, said rotary drive containing means including a first threaded shaft engaging said pin for adjusting the eccentricity of said pin with respect to the axis of rotation of said drive and, thus,- for adjusting the maximum velocity and amplitude of oscillation of said first lever about said pivot point, a second sliding block mounted in said first lever, a push rod pivotably coupled at one end thereof to said second sliding block, means including a second threaded shaft for changing the distance between said second sliding blockand said pivot point of said first lever to change the amplitude of push rod oscillatory motion with respect to the amplitude of oscillation of said first lever, whereby both the maximum velocity and maximum displacement of the mold can be adjusted independently.

2. Apparatus in accordance with claim 1 in which the length of said push rod is adjustable.

3. Apparatus in accordance with claim 2 in which said means coupling said push rod to said mold comprises a pivotably mounted beam, one end of said beam being coupled to said push rod and the other end of said beam being coupled to said mold.

4. Continuous casting apparatus comprising a mold, guide means defining the oscillation path of said mold, a beam, a pivot, said beam being pivotably mounted on said pivot, means for slidably coupling said beam to said mold to reciprocate the mold in accordance with reciprocation of said beam, and rotating drive means to reciprocate said beam in a reciprocation cycle about said pivot, said drive means being slidably coupled to said beam so that the lever arm between the pivot and the position of coupling said drive means to said beam varies in cyclic manner between a minimum and a maximum during the reciprocation cycle, said beam being pivotably mounted at one end thereof, said beam comprising a frame, a central shaft extending lengthwise of said beam, a sliding bushing on said shaft, said bushing being coupled to said push rod, a sliding block slidably mounted within said frame, a drive shaft, an eccentric pin mounted thereon, and bearing means coupling said eccentric pin to said sliding block.

References Cited by the Examiner UNITED STATES PATENTS 1,614,554 1/1927 Holn 7448 2,169,493 8/1939 Humphrey 74-45 2,454,256 1 l/ 1948 Myers 7445 2,871,530 2/ 1959 Weiland 2257.2

FOREIGN PATENTS 1,327,633 4/ 1963 France.

I SPENCER OVERHOLSER, Primary Examiner.

R. S. ANNEAR, Assistant Examiner. 

1. A CONTINUOUS CASTING APPARATUS COMPRISING A MOLD, GUIDE MEANS DEFINING THE OSCILLATION PATH OF SAID MOLD, ROTARY DRIVE MEANS, SAID ROTARY DRIVE MEANS BEING PROVIDED WITH A PIN ECCENTRIC TO THE AXIS OF ROTATION THEREOF, A PIVOTABLY MOUNTED FIRST LEVER, A FIRST SLIDING BLOCK SLIDABLE MOUNTED WITHIN SAID FIRST LEVER AND ENGAGED BY SAID ECCENTRIIC PIN ON SAID ROTARY DRIVE, THE PATH OF MOVEMENT OF SAID FIRST SLIDING BLOCK WITHIN SAID LEVER BEING CNFINED TO AND DISPLACED TO ONE SIDE OF THE PIVOT POINT OF SAID FIRST LEVER TO CONVERT THE ROTARY MOTION OF SAID ROTARY DRIVE TRANSMITED THROUGH THE ECCENTRIC PIN ENGAGEMENT WITH SAID FIRST SLIDING BLOCK TO OSCILLATORY MOTION OF SAID PIVOTED FIRST LEVER, SAID ROTARY DRIVE CONTAINING MEANS INCLUDING A FIRST THREADED SHAFT ENGAGING SAID PIN FOR ADJUSTING THE ECCENTRICITY OF SAID PIN WITH RESPECT TO THE AXIS OF ROTATION OF SAID DRIVE AND THUS, FOR ADJUSTING THE MAXIMUM VELOCITY AND AMPLITUDE OF OSCILLATION OF SAID FIRST LEVER ABOUT SAID PIVOT POINT, A SECOND SLIDING BLOCK MOUNTED IN SAID FIRST LEVER, A PUSH ROD PIVOTABLY COUPLED AT ONE END THEREOF TO SAID SECOND SLIDING BLOCK, MEANS INCLUDING A SECOND THREADED SHAFT FOR CHANGING THE DISTANCE BETWEEN SAID SECOND SLIDING BLOCK AND SAID PIVOT POINT OF SAID FIRST LEVER TO CHANGE THE AMPLITUDE OF PUSH ROD OSCIALLATORY MOTION WITH RESPECT TO THE AMPLITUDE OF OSCILLATION OF SAID FIRST LEVER, WHEREBY BOTH THE MAXIMUM VELOCITY AND MAXIMUM DISPLACEMENT OF THE MOLD CAN BE ADJUSTED INDEPENEDENTLY. 